drivers/gpu/ion/ion_iommu_heap.c - kernel/msm - Gitiles

 /*
  * Copyright (c) 2011-2013, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
  * only version 2 as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/msm_ion.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/iommu.h>
 #include <linux/pfn.h>
 #include <linux/dma-mapping.h>
 #include "ion_priv.h"

 #include <asm/mach/map.h>
 #include <asm/page.h>
 #include <asm/cacheflush.h>
 #include <mach/iommu_domains.h>
 #include <trace/events/kmem.h>

 struct ion_iommu_heap {
 	struct ion_heap heap;
 	struct ion_page_pool **cached_pools;
 	struct ion_page_pool **uncached_pools;
 };

 /*
  * We will attempt to allocate high-order pages and store those in an
  * sg_list. However, some APIs expect an array of struct page * where
  * each page is of size PAGE_SIZE. We use this extra structure to
  * carry around an array of such pages (derived from the high-order
  * pages with nth_page).
  */
 struct ion_iommu_priv_data {
 	struct page **pages;
 	unsigned int pages_uses_vmalloc;
 	int nrpages;
 	unsigned long size;
 };

 #define MAX_VMAP_RETRIES 10
 #define BAD_ORDER	-1

 static const unsigned int orders[] = {9, 8, 4, 0};
 static const int num_orders = ARRAY_SIZE(orders);
 static unsigned int low_gfp_flags = __GFP_HIGHMEM | GFP_KERNEL | __GFP_ZERO;
 static unsigned int high_gfp_flags = (__GFP_HIGHMEM | __GFP_NORETRY
 				| __GFP_NO_KSWAPD | __GFP_NOWARN |
 				 __GFP_IO | __GFP_FS | __GFP_ZERO);

 struct page_info {
 	struct page *page;
 	unsigned int order;
 	struct list_head list;
 };

 static int order_to_index(unsigned int order)
 {
 	int i;
 	for (i = 0; i < num_orders; i++)
 		if (order == orders[i])
 			return i;
 	BUG();
 	return BAD_ORDER;
 }

 static unsigned int order_to_size(int order)
 {
 	return PAGE_SIZE << order;
 }

 static struct page_info *alloc_largest_available(struct ion_iommu_heap *heap,
 						unsigned long size,
 						unsigned int max_order,
 						unsigned long flags)
 {
 	struct page *page;
 	struct page_info *info;
 	int i;

 	for (i = 0; i < num_orders; i++) {
 		gfp_t gfp;
 		int idx = order_to_index(orders[i]);
 		struct ion_page_pool *pool;

 		if (idx == BAD_ORDER)
 			continue;

 		if (ION_IS_CACHED(flags)) {
 			pool = heap->cached_pools[idx];
 			BUG_ON(!pool);
 		} else {
 			pool = heap->uncached_pools[idx];
 			BUG_ON(!pool);
 		}

 		if (size < order_to_size(orders[i]))
 			continue;
 		if (max_order < orders[i])
 			continue;

 		if (orders[i]) {
 			gfp = high_gfp_flags;
 		} else {
 			gfp = low_gfp_flags;
 		}
 		trace_alloc_pages_iommu_start(gfp, orders[i]);
 		if (flags & ION_FLAG_POOL_FORCE_ALLOC)
 			page = alloc_pages(gfp, orders[i]);
 		else
 			page = ion_page_pool_alloc(pool);
 		trace_alloc_pages_iommu_end(gfp, orders[i]);
 		if (!page) {
 			trace_alloc_pages_iommu_fail(gfp, orders[i]);
 			continue;
 		}

 		info = kmalloc(sizeof(struct page_info), GFP_KERNEL);
 		if (info) {
 			info->page = page;
 			info->order = orders[i];
 		}
 		return info;
 	}
 	return NULL;
 }

 static int ion_iommu_buffer_zero(struct ion_iommu_priv_data *data)
 {
 	int i, j;
 	unsigned int npages_to_vmap;
 	unsigned int total_pages;
 	void *ptr = NULL;

 	/*
 	 * As an optimization, we manually zero out all of the
 	 * pages in one fell swoop here. To safeguard against
 	 * insufficient vmalloc space, we only vmap
 	 * `npages_to_vmap' at a time, starting with a
 	 * conservative estimate of 1/8 of the total number of
 	 * vmalloc pages available. Note that the `pages'
 	 * array is composed of all 4K pages, irrespective of
 	 * the size of the pages on the sg list.
 	 */
 	npages_to_vmap = ((VMALLOC_END - VMALLOC_START)/8)
 			>> PAGE_SHIFT;
 	total_pages = data->nrpages;
 	for (i = 0; i < total_pages; i += npages_to_vmap) {
 		npages_to_vmap = min(npages_to_vmap, total_pages - i);
 		for (j = 0; j < MAX_VMAP_RETRIES && npages_to_vmap;
 			++j) {
 			ptr = vmap(&data->pages[i], npages_to_vmap,
 					VM_IOREMAP, pgprot_kernel);
 			if (ptr)
 				break;
 			else
 				npages_to_vmap >>= 1;
 		}
 		if (!ptr)
 			return -ENOMEM;

 		memset(ptr, 0, npages_to_vmap * PAGE_SIZE);
 		vunmap(ptr);
 	}

 	return 0;
 }

 static int ion_iommu_heap_allocate(struct ion_heap *heap,
 				      struct ion_buffer *buffer,
 				      unsigned long size, unsigned long align,
 				      unsigned long flags)
 {
 	int ret, i;
 	struct list_head pages_list;
 	struct page_info *info, *tmp_info;
 	struct ion_iommu_priv_data *data = NULL;
 	struct ion_iommu_heap *iommu_heap =
 		container_of(heap, struct ion_iommu_heap, heap);

 	if (msm_use_iommu()) {
 		struct scatterlist *sg;
 		struct sg_table *table;
 		int j;
 		unsigned int num_large_pages = 0;
 		unsigned long size_remaining = PAGE_ALIGN(size);
 		unsigned int max_order = ION_IS_CACHED(flags) ? 0 : orders[0];
 		unsigned int page_tbl_size;

 		data = kmalloc(sizeof(*data), GFP_KERNEL);
 		if (!data)
 			return -ENOMEM;

 		INIT_LIST_HEAD(&pages_list);
 		while (size_remaining > 0) {
 			info = alloc_largest_available(iommu_heap,
 						size_remaining,
 						max_order,
 						flags);
 			if (!info) {
 				ret = -ENOMEM;
 				goto err_free_data;
 			}
 			list_add_tail(&info->list, &pages_list);
 			size_remaining -= order_to_size(info->order);
 			max_order = info->order;
 			num_large_pages++;
 		}

 		data->size = PFN_ALIGN(size);
 		data->nrpages = data->size >> PAGE_SHIFT;
 		data->pages_uses_vmalloc = 0;
 		page_tbl_size = sizeof(struct page *) * data->nrpages;

 		if (page_tbl_size > SZ_8K) {
 			/*
 			 * Do fallback to ensure we have a balance between
 			 * performance and availability.
 			 */
 			data->pages = kmalloc(page_tbl_size,
 					      __GFP_COMP | __GFP_NORETRY |
 					      __GFP_NO_KSWAPD | __GFP_NOWARN);
 			if (!data->pages) {
 				data->pages = vmalloc(page_tbl_size);
 				data->pages_uses_vmalloc = 1;
 			}
 		} else {
 			data->pages = kmalloc(page_tbl_size, GFP_KERNEL);
 		}
 		if (!data->pages) {
 			ret = -ENOMEM;
 			goto err_free_data;
 		}

 		table = buffer->sg_table =
 				kzalloc(sizeof(struct sg_table), GFP_KERNEL);

 		if (!table) {
 			ret = -ENOMEM;
 			goto err1;
 		}
 		ret = sg_alloc_table(table, num_large_pages, GFP_KERNEL);
 		if (ret)
 			goto err2;

 		i = 0;
 		sg = table->sgl;
 		list_for_each_entry_safe(info, tmp_info, &pages_list, list) {
 			struct page *page = info->page;
 			sg_set_page(sg, page, order_to_size(info->order), 0);
 			sg_dma_address(sg) = sg_phys(sg);
 			sg = sg_next(sg);
 			for (j = 0; j < (1 << info->order); ++j)
 				data->pages[i++] = nth_page(page, j);
 			list_del(&info->list);
 			kfree(info);
 		}


 		if (flags & ION_FLAG_POOL_FORCE_ALLOC) {
 			ret = ion_iommu_buffer_zero(data);
 			if (ret) {
 				pr_err("Couldn't vmap the pages for zeroing\n");
 				goto err3;
 			}


 			if (!ION_IS_CACHED(flags))
 				dma_sync_sg_for_device(NULL, table->sgl,
 						table->nents,
 						DMA_BIDIRECTIONAL);

 		}
 		buffer->priv_virt = data;
 		return 0;

 	} else {
 		return -ENOMEM;
 	}


 err3:
 	sg_free_table(buffer->sg_table);
 err2:
 	kfree(buffer->sg_table);
 	buffer->sg_table = 0;
 err1:
 	if (data->pages_uses_vmalloc)
 		vfree(data->pages);
 	else
 		kfree(data->pages);
 err_free_data:
 	kfree(data);

 	list_for_each_entry_safe(info, tmp_info, &pages_list, list) {
 		if (info->page)
 			__free_pages(info->page, info->order);
 		list_del(&info->list);
 		kfree(info);
 	}
 	return ret;
 }

 static void ion_iommu_heap_free(struct ion_buffer *buffer)
 {
 	int i;
 	struct scatterlist *sg;
 	struct sg_table *table = buffer->sg_table;
 	struct ion_iommu_priv_data *data = buffer->priv_virt;
 	bool cached = ion_buffer_cached(buffer);
 	struct ion_iommu_heap *iommu_heap =
 	     container_of(buffer->heap, struct	ion_iommu_heap, heap);

 	if (!table)
 		return;
 	if (!data)
 		return;

 	if (!(buffer->flags & ION_FLAG_POOL_FORCE_ALLOC))
 		ion_iommu_buffer_zero(data);

 	for_each_sg(table->sgl, sg, table->nents, i) {
 		int order = get_order(sg_dma_len(sg));
 		int idx = order_to_index(order);
 		struct ion_page_pool *pool;

 		if (idx == BAD_ORDER) {
 			WARN_ON(1);
 			continue;
 		}

 		if (cached)
 			pool = iommu_heap->cached_pools[idx];
 		else
 			pool = iommu_heap->uncached_pools[idx];

 		if (buffer->flags & ION_FLAG_POOL_FORCE_ALLOC)
 			__free_pages(sg_page(sg), order);
 		else
 			ion_page_pool_free(pool, sg_page(sg));
 	}

 	sg_free_table(table);
 	kfree(table);
 	table = 0;
 	if (data->pages_uses_vmalloc)
 		vfree(data->pages);
 	else
 		kfree(data->pages);
 	kfree(data);
 }

 void *ion_iommu_heap_map_kernel(struct ion_heap *heap,
 				struct ion_buffer *buffer)
 {
 	struct ion_iommu_priv_data *data = buffer->priv_virt;
 	pgprot_t page_prot = PAGE_KERNEL;

 	if (!data)
 		return NULL;

 	if (!ION_IS_CACHED(buffer->flags))
 		page_prot = pgprot_writecombine(page_prot);

 	buffer->vaddr = vmap(data->pages, data->nrpages, VM_IOREMAP, page_prot);

 	return buffer->vaddr;
 }

 void ion_iommu_heap_unmap_kernel(struct ion_heap *heap,
 				    struct ion_buffer *buffer)
 {
 	if (!buffer->vaddr)
 		return;

 	vunmap(buffer->vaddr);
 	buffer->vaddr = NULL;
 }

 int ion_iommu_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
 			       struct vm_area_struct *vma)
 {
 	struct sg_table *table = buffer->sg_table;
 	unsigned long addr = vma->vm_start;
 	unsigned long offset = vma->vm_pgoff * PAGE_SIZE;
 	struct scatterlist *sg;
 	int i;

 	if (!ION_IS_CACHED(buffer->flags))
 		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

 	for_each_sg(table->sgl, sg, table->nents, i) {
 		struct page *page = sg_page(sg);
 		unsigned long remainder = vma->vm_end - addr;
 		unsigned long len = sg_dma_len(sg);

 		if (offset >= sg_dma_len(sg)) {
 			offset -= sg_dma_len(sg);
 			continue;
 		} else if (offset) {
 			page += offset / PAGE_SIZE;
 			len = sg_dma_len(sg) - offset;
 			offset = 0;
 		}
 		len = min(len, remainder);
 		remap_pfn_range(vma, addr, page_to_pfn(page), len,
 				vma->vm_page_prot);
 		addr += len;
 		if (addr >= vma->vm_end)
 			return 0;
 	}
 	return 0;
 }

 static struct sg_table *ion_iommu_heap_map_dma(struct ion_heap *heap,
 					      struct ion_buffer *buffer)
 {
 	return buffer->sg_table;
 }

 static void ion_iommu_heap_unmap_dma(struct ion_heap *heap,
 				 struct ion_buffer *buffer)
 {
 }

 static int ion_iommu_heap_debug_show(struct ion_heap *heap, struct seq_file *s,
 					void *unused)
 {

 	struct ion_iommu_heap *iommu_heap = container_of(heap,
 							struct ion_iommu_heap,
 							heap);
 	int i;
 	unsigned long total = 0;

 	seq_printf(s, "Cached Pools:\n");
 	for (i = 0; i < num_orders; i++) {
 		struct ion_page_pool *pool = iommu_heap->cached_pools[i];
 		seq_printf(s, "%d order %u highmem pages in pool = %lx total\n",
 			   pool->high_count, pool->order,
 			   (1 << pool->order) * PAGE_SIZE * pool->high_count);
 		seq_printf(s, "%d order %u lowmem pages in pool = %lx total\n",
 			   pool->low_count, pool->order,
 			   (1 << pool->order) * PAGE_SIZE * pool->low_count);

 		total += (1 << pool->order) * PAGE_SIZE *
 			  (pool->low_count + pool->high_count);
 	}

 	seq_printf(s, "Uncached Pools:\n");
 	for (i = 0; i < num_orders; i++) {
 		struct ion_page_pool *pool = iommu_heap->uncached_pools[i];
 		seq_printf(s, "%d order %u highmem pages in pool = %lx total\n",
 			   pool->high_count, pool->order,
 			   (1 << pool->order) * PAGE_SIZE * pool->high_count);
 		seq_printf(s, "%d order %u lowmem pages in pool = %lx total\n",
 			   pool->low_count, pool->order,
 			   (1 << pool->order) * PAGE_SIZE * pool->low_count);

 		total += (1 << pool->order) * PAGE_SIZE *
 			  (pool->low_count + pool->high_count);
 	}
 	seq_printf(s, "Total bytes in pool: %lx\n", total);
 	return 0;
 }

 static struct ion_heap_ops iommu_heap_ops = {
 	.allocate = ion_iommu_heap_allocate,
 	.free = ion_iommu_heap_free,
 	.map_user = ion_iommu_heap_map_user,
 	.map_kernel = ion_iommu_heap_map_kernel,
 	.unmap_kernel = ion_iommu_heap_unmap_kernel,
 	.map_dma = ion_iommu_heap_map_dma,
 	.unmap_dma = ion_iommu_heap_unmap_dma,
 };

 struct ion_heap *ion_iommu_heap_create(struct ion_platform_heap *heap_data)
 {
 	struct ion_iommu_heap *iommu_heap;
 	int i;

 	iommu_heap = kzalloc(sizeof(struct ion_iommu_heap), GFP_KERNEL);
 	if (!iommu_heap)
 		return ERR_PTR(-ENOMEM);

 	iommu_heap->heap.ops = &iommu_heap_ops;
 	iommu_heap->heap.type = ION_HEAP_TYPE_IOMMU;
 	iommu_heap->uncached_pools = kzalloc(
 			      sizeof(struct ion_page_pool *) * num_orders,
 			      GFP_KERNEL);
 	if (!iommu_heap->uncached_pools)
 		goto err_alloc_uncached_pools;

 	iommu_heap->cached_pools = kzalloc(
 			      sizeof(struct ion_page_pool *) * num_orders,
 			      GFP_KERNEL);

 	if (!iommu_heap->cached_pools)
 		goto err_alloc_cached_pools;

 	for (i = 0; i < num_orders; i++) {
 		struct ion_page_pool *pool;
 		gfp_t gfp_flags;

 		if (orders[i])
 			gfp_flags = high_gfp_flags | __GFP_ZERO;
 		else
 			gfp_flags = low_gfp_flags | __GFP_ZERO;
 		pool = ion_page_pool_create(gfp_flags, orders[i]);
 		if (!pool)
 			goto err_create_cached_pool;
 		iommu_heap->cached_pools[i] = pool;
 	}

 	for (i = 0; i < num_orders; i++) {
 		struct ion_page_pool *pool;
 		gfp_t gfp_flags;

 		if (orders[i])
 			gfp_flags = high_gfp_flags | __GFP_ZERO;
 		else
 			gfp_flags = low_gfp_flags | __GFP_ZERO;
 		pool = ion_page_pool_create(gfp_flags, orders[i]);
 		if (!pool)
 			goto err_create_uncached_pool;
 		iommu_heap->uncached_pools[i] = pool;
 	}
 	iommu_heap->heap.debug_show = ion_iommu_heap_debug_show;
 	return &iommu_heap->heap;

 err_create_uncached_pool:
 	for (i = 0; i < num_orders; i++)
 		if (iommu_heap->cached_pools[i])
 			ion_page_pool_destroy(iommu_heap->uncached_pools[i]);


 err_create_cached_pool:
 	for (i = 0; i < num_orders; i++)
 		if (iommu_heap->uncached_pools[i])
 			ion_page_pool_destroy(iommu_heap->cached_pools[i]);

 	kfree(iommu_heap->cached_pools);
 err_alloc_cached_pools:
 	kfree(iommu_heap->uncached_pools);
 err_alloc_uncached_pools:
 	kfree(iommu_heap);
 	return ERR_PTR(-ENOMEM);
 }

 void ion_iommu_heap_destroy(struct ion_heap *heap)
 {
 	struct ion_iommu_heap *iommu_heap =
 	     container_of(heap, struct  ion_iommu_heap, heap);

 	kfree(iommu_heap);
 	iommu_heap = NULL;
 }
	/*
	* Copyright (c) 2011-2013, The Linux Foundation. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 and
	* only version 2 as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/msm_ion.h>
	#include <linux/mm.h>
	#include <linux/highmem.h>
	#include <linux/scatterlist.h>
	#include <linux/slab.h>
	#include <linux/vmalloc.h>
	#include <linux/iommu.h>
	#include <linux/pfn.h>
	#include <linux/dma-mapping.h>
	#include "ion_priv.h"

	#include <asm/mach/map.h>
	#include <asm/page.h>
	#include <asm/cacheflush.h>
	#include <mach/iommu_domains.h>
	#include <trace/events/kmem.h>

	struct ion_iommu_heap {
	struct ion_heap heap;
	struct ion_page_pool **cached_pools;
	struct ion_page_pool **uncached_pools;
	};

	/*
	* We will attempt to allocate high-order pages and store those in an
	* sg_list. However, some APIs expect an array of struct page * where
	* each page is of size PAGE_SIZE. We use this extra structure to
	* carry around an array of such pages (derived from the high-order
	* pages with nth_page).
	*/
	struct ion_iommu_priv_data {
	struct page **pages;
	unsigned int pages_uses_vmalloc;
	int nrpages;
	unsigned long size;
	};

	#define MAX_VMAP_RETRIES 10
	#define BAD_ORDER -1

	static const unsigned int orders[] = {9, 8, 4, 0};
	static const int num_orders = ARRAY_SIZE(orders);
	static unsigned int low_gfp_flags = __GFP_HIGHMEM \| GFP_KERNEL \| __GFP_ZERO;
	static unsigned int high_gfp_flags = (__GFP_HIGHMEM \| __GFP_NORETRY
	\| __GFP_NO_KSWAPD \| __GFP_NOWARN \|
	__GFP_IO \| __GFP_FS \| __GFP_ZERO);

	struct page_info {
	struct page *page;
	unsigned int order;
	struct list_head list;
	};

	static int order_to_index(unsigned int order)
	{
	int i;
	for (i = 0; i < num_orders; i++)
	if (order == orders[i])
	return i;
	BUG();
	return BAD_ORDER;
	}

	static unsigned int order_to_size(int order)
	{
	return PAGE_SIZE << order;
	}

	static struct page_info alloc_largest_available(struct ion_iommu_heap heap,
	unsigned long size,
	unsigned int max_order,
	unsigned long flags)
	{
	struct page *page;
	struct page_info *info;
	int i;

	for (i = 0; i < num_orders; i++) {
	gfp_t gfp;
	int idx = order_to_index(orders[i]);
	struct ion_page_pool *pool;

	if (idx == BAD_ORDER)
	continue;

	if (ION_IS_CACHED(flags)) {
	pool = heap->cached_pools[idx];
	BUG_ON(!pool);
	} else {
	pool = heap->uncached_pools[idx];
	BUG_ON(!pool);
	}

	if (size < order_to_size(orders[i]))
	continue;
	if (max_order < orders[i])
	continue;

	if (orders[i]) {
	gfp = high_gfp_flags;
	} else {
	gfp = low_gfp_flags;
	}
	trace_alloc_pages_iommu_start(gfp, orders[i]);
	if (flags & ION_FLAG_POOL_FORCE_ALLOC)
	page = alloc_pages(gfp, orders[i]);
	else
	page = ion_page_pool_alloc(pool);
	trace_alloc_pages_iommu_end(gfp, orders[i]);
	if (!page) {
	trace_alloc_pages_iommu_fail(gfp, orders[i]);
	continue;
	}

	info = kmalloc(sizeof(struct page_info), GFP_KERNEL);
	if (info) {
	info->page = page;
	info->order = orders[i];
	}
	return info;
	}
	return NULL;
	}

	static int ion_iommu_buffer_zero(struct ion_iommu_priv_data *data)
	{
	int i, j;
	unsigned int npages_to_vmap;
	unsigned int total_pages;
	void *ptr = NULL;

	/*
	* As an optimization, we manually zero out all of the
	* pages in one fell swoop here. To safeguard against
	* insufficient vmalloc space, we only vmap
	* `npages_to_vmap' at a time, starting with a
	* conservative estimate of 1/8 of the total number of
	* vmalloc pages available. Note that the `pages'
	* array is composed of all 4K pages, irrespective of
	* the size of the pages on the sg list.
	*/
	npages_to_vmap = ((VMALLOC_END - VMALLOC_START)/8)
	>> PAGE_SHIFT;
	total_pages = data->nrpages;
	for (i = 0; i < total_pages; i += npages_to_vmap) {
	npages_to_vmap = min(npages_to_vmap, total_pages - i);
	for (j = 0; j < MAX_VMAP_RETRIES && npages_to_vmap;
	++j) {
	ptr = vmap(&data->pages[i], npages_to_vmap,
	VM_IOREMAP, pgprot_kernel);
	if (ptr)
	break;
	else
	npages_to_vmap >>= 1;
	}
	if (!ptr)
	return -ENOMEM;

	memset(ptr, 0, npages_to_vmap * PAGE_SIZE);
	vunmap(ptr);
	}

	return 0;
	}

	static int ion_iommu_heap_allocate(struct ion_heap *heap,
	struct ion_buffer *buffer,
	unsigned long size, unsigned long align,
	unsigned long flags)
	{
	int ret, i;
	struct list_head pages_list;
	struct page_info info, tmp_info;
	struct ion_iommu_priv_data *data = NULL;
	struct ion_iommu_heap *iommu_heap =
	container_of(heap, struct ion_iommu_heap, heap);

	if (msm_use_iommu()) {
	struct scatterlist *sg;
	struct sg_table *table;
	int j;
	unsigned int num_large_pages = 0;
	unsigned long size_remaining = PAGE_ALIGN(size);
	unsigned int max_order = ION_IS_CACHED(flags) ? 0 : orders[0];
	unsigned int page_tbl_size;

	data = kmalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	INIT_LIST_HEAD(&pages_list);
	while (size_remaining > 0) {
	info = alloc_largest_available(iommu_heap,
	size_remaining,
	max_order,
	flags);
	if (!info) {
	ret = -ENOMEM;
	goto err_free_data;
	}
	list_add_tail(&info->list, &pages_list);
	size_remaining -= order_to_size(info->order);
	max_order = info->order;
	num_large_pages++;
	}

	data->size = PFN_ALIGN(size);
	data->nrpages = data->size >> PAGE_SHIFT;
	data->pages_uses_vmalloc = 0;
	page_tbl_size = sizeof(struct page ) data->nrpages;

	if (page_tbl_size > SZ_8K) {
	/*
	* Do fallback to ensure we have a balance between
	* performance and availability.
	*/
	data->pages = kmalloc(page_tbl_size,
	__GFP_COMP \| __GFP_NORETRY \|
	__GFP_NO_KSWAPD \| __GFP_NOWARN);
	if (!data->pages) {
	data->pages = vmalloc(page_tbl_size);
	data->pages_uses_vmalloc = 1;
	}
	} else {
	data->pages = kmalloc(page_tbl_size, GFP_KERNEL);
	}
	if (!data->pages) {
	ret = -ENOMEM;
	goto err_free_data;
	}

	table = buffer->sg_table =
	kzalloc(sizeof(struct sg_table), GFP_KERNEL);

	if (!table) {
	ret = -ENOMEM;
	goto err1;
	}
	ret = sg_alloc_table(table, num_large_pages, GFP_KERNEL);
	if (ret)
	goto err2;

	i = 0;
	sg = table->sgl;
	list_for_each_entry_safe(info, tmp_info, &pages_list, list) {
	struct page *page = info->page;
	sg_set_page(sg, page, order_to_size(info->order), 0);
	sg_dma_address(sg) = sg_phys(sg);
	sg = sg_next(sg);
	for (j = 0; j < (1 << info->order); ++j)
	data->pages[i++] = nth_page(page, j);
	list_del(&info->list);
	kfree(info);
	}


	if (flags & ION_FLAG_POOL_FORCE_ALLOC) {
	ret = ion_iommu_buffer_zero(data);
	if (ret) {
	pr_err("Couldn't vmap the pages for zeroing\n");
	goto err3;
	}


	if (!ION_IS_CACHED(flags))
	dma_sync_sg_for_device(NULL, table->sgl,
	table->nents,
	DMA_BIDIRECTIONAL);

	}
	buffer->priv_virt = data;
	return 0;

	} else {
	return -ENOMEM;
	}


	err3:
	sg_free_table(buffer->sg_table);
	err2:
	kfree(buffer->sg_table);
	buffer->sg_table = 0;
	err1:
	if (data->pages_uses_vmalloc)
	vfree(data->pages);
	else
	kfree(data->pages);
	err_free_data:
	kfree(data);

	list_for_each_entry_safe(info, tmp_info, &pages_list, list) {
	if (info->page)
	__free_pages(info->page, info->order);
	list_del(&info->list);
	kfree(info);
	}
	return ret;
	}

	static void ion_iommu_heap_free(struct ion_buffer *buffer)
	{
	int i;
	struct scatterlist *sg;
	struct sg_table *table = buffer->sg_table;
	struct ion_iommu_priv_data *data = buffer->priv_virt;
	bool cached = ion_buffer_cached(buffer);
	struct ion_iommu_heap *iommu_heap =
	container_of(buffer->heap, struct ion_iommu_heap, heap);

	if (!table)
	return;
	if (!data)
	return;

	if (!(buffer->flags & ION_FLAG_POOL_FORCE_ALLOC))
	ion_iommu_buffer_zero(data);

	for_each_sg(table->sgl, sg, table->nents, i) {
	int order = get_order(sg_dma_len(sg));
	int idx = order_to_index(order);
	struct ion_page_pool *pool;

	if (idx == BAD_ORDER) {
	WARN_ON(1);
	continue;
	}

	if (cached)
	pool = iommu_heap->cached_pools[idx];
	else
	pool = iommu_heap->uncached_pools[idx];

	if (buffer->flags & ION_FLAG_POOL_FORCE_ALLOC)
	__free_pages(sg_page(sg), order);
	else
	ion_page_pool_free(pool, sg_page(sg));
	}

	sg_free_table(table);
	kfree(table);
	table = 0;
	if (data->pages_uses_vmalloc)
	vfree(data->pages);
	else
	kfree(data->pages);
	kfree(data);
	}

	void ion_iommu_heap_map_kernel(struct ion_heap heap,
	struct ion_buffer *buffer)
	{
	struct ion_iommu_priv_data *data = buffer->priv_virt;
	pgprot_t page_prot = PAGE_KERNEL;

	if (!data)
	return NULL;

	if (!ION_IS_CACHED(buffer->flags))
	page_prot = pgprot_writecombine(page_prot);

	buffer->vaddr = vmap(data->pages, data->nrpages, VM_IOREMAP, page_prot);

	return buffer->vaddr;
	}

	void ion_iommu_heap_unmap_kernel(struct ion_heap *heap,
	struct ion_buffer *buffer)
	{
	if (!buffer->vaddr)
	return;

	vunmap(buffer->vaddr);
	buffer->vaddr = NULL;
	}

	int ion_iommu_heap_map_user(struct ion_heap heap, struct ion_buffer buffer,
	struct vm_area_struct *vma)
	{
	struct sg_table *table = buffer->sg_table;
	unsigned long addr = vma->vm_start;
	unsigned long offset = vma->vm_pgoff * PAGE_SIZE;
	struct scatterlist *sg;
	int i;

	if (!ION_IS_CACHED(buffer->flags))
	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

	for_each_sg(table->sgl, sg, table->nents, i) {
	struct page *page = sg_page(sg);
	unsigned long remainder = vma->vm_end - addr;
	unsigned long len = sg_dma_len(sg);

	if (offset >= sg_dma_len(sg)) {
	offset -= sg_dma_len(sg);
	continue;
	} else if (offset) {
	page += offset / PAGE_SIZE;
	len = sg_dma_len(sg) - offset;
	offset = 0;
	}
	len = min(len, remainder);
	remap_pfn_range(vma, addr, page_to_pfn(page), len,
	vma->vm_page_prot);
	addr += len;
	if (addr >= vma->vm_end)
	return 0;
	}
	return 0;
	}

	static struct sg_table ion_iommu_heap_map_dma(struct ion_heap heap,
	struct ion_buffer *buffer)
	{
	return buffer->sg_table;
	}

	static void ion_iommu_heap_unmap_dma(struct ion_heap *heap,
	struct ion_buffer *buffer)
	{
	}

	static int ion_iommu_heap_debug_show(struct ion_heap heap, struct seq_file s,
	void *unused)
	{

	struct ion_iommu_heap *iommu_heap = container_of(heap,
	struct ion_iommu_heap,
	heap);
	int i;
	unsigned long total = 0;

	seq_printf(s, "Cached Pools:\n");
	for (i = 0; i < num_orders; i++) {
	struct ion_page_pool *pool = iommu_heap->cached_pools[i];
	seq_printf(s, "%d order %u highmem pages in pool = %lx total\n",
	pool->high_count, pool->order,
	(1 << pool->order) * PAGE_SIZE * pool->high_count);
	seq_printf(s, "%d order %u lowmem pages in pool = %lx total\n",
	pool->low_count, pool->order,
	(1 << pool->order) * PAGE_SIZE * pool->low_count);

	total += (1 << pool->order) * PAGE_SIZE *
	(pool->low_count + pool->high_count);
	}

	seq_printf(s, "Uncached Pools:\n");
	for (i = 0; i < num_orders; i++) {
	struct ion_page_pool *pool = iommu_heap->uncached_pools[i];
	seq_printf(s, "%d order %u highmem pages in pool = %lx total\n",
	pool->high_count, pool->order,
	(1 << pool->order) * PAGE_SIZE * pool->high_count);
	seq_printf(s, "%d order %u lowmem pages in pool = %lx total\n",
	pool->low_count, pool->order,
	(1 << pool->order) * PAGE_SIZE * pool->low_count);

	total += (1 << pool->order) * PAGE_SIZE *
	(pool->low_count + pool->high_count);
	}
	seq_printf(s, "Total bytes in pool: %lx\n", total);
	return 0;
	}

	static struct ion_heap_ops iommu_heap_ops = {
	.allocate = ion_iommu_heap_allocate,
	.free = ion_iommu_heap_free,
	.map_user = ion_iommu_heap_map_user,
	.map_kernel = ion_iommu_heap_map_kernel,
	.unmap_kernel = ion_iommu_heap_unmap_kernel,
	.map_dma = ion_iommu_heap_map_dma,
	.unmap_dma = ion_iommu_heap_unmap_dma,
	};

	struct ion_heap ion_iommu_heap_create(struct ion_platform_heap heap_data)
	{
	struct ion_iommu_heap *iommu_heap;
	int i;

	iommu_heap = kzalloc(sizeof(struct ion_iommu_heap), GFP_KERNEL);
	if (!iommu_heap)
	return ERR_PTR(-ENOMEM);

	iommu_heap->heap.ops = &iommu_heap_ops;
	iommu_heap->heap.type = ION_HEAP_TYPE_IOMMU;
	iommu_heap->uncached_pools = kzalloc(
	sizeof(struct ion_page_pool ) num_orders,
	GFP_KERNEL);
	if (!iommu_heap->uncached_pools)
	goto err_alloc_uncached_pools;

	iommu_heap->cached_pools = kzalloc(
	sizeof(struct ion_page_pool ) num_orders,
	GFP_KERNEL);

	if (!iommu_heap->cached_pools)
	goto err_alloc_cached_pools;

	for (i = 0; i < num_orders; i++) {
	struct ion_page_pool *pool;
	gfp_t gfp_flags;

	if (orders[i])
	gfp_flags = high_gfp_flags \| __GFP_ZERO;
	else
	gfp_flags = low_gfp_flags \| __GFP_ZERO;
	pool = ion_page_pool_create(gfp_flags, orders[i]);
	if (!pool)
	goto err_create_cached_pool;
	iommu_heap->cached_pools[i] = pool;
	}

	for (i = 0; i < num_orders; i++) {
	struct ion_page_pool *pool;
	gfp_t gfp_flags;

	if (orders[i])
	gfp_flags = high_gfp_flags \| __GFP_ZERO;
	else
	gfp_flags = low_gfp_flags \| __GFP_ZERO;
	pool = ion_page_pool_create(gfp_flags, orders[i]);
	if (!pool)
	goto err_create_uncached_pool;
	iommu_heap->uncached_pools[i] = pool;
	}
	iommu_heap->heap.debug_show = ion_iommu_heap_debug_show;
	return &iommu_heap->heap;

	err_create_uncached_pool:
	for (i = 0; i < num_orders; i++)
	if (iommu_heap->cached_pools[i])
	ion_page_pool_destroy(iommu_heap->uncached_pools[i]);


	err_create_cached_pool:
	for (i = 0; i < num_orders; i++)
	if (iommu_heap->uncached_pools[i])
	ion_page_pool_destroy(iommu_heap->cached_pools[i]);

	kfree(iommu_heap->cached_pools);
	err_alloc_cached_pools:
	kfree(iommu_heap->uncached_pools);
	err_alloc_uncached_pools:
	kfree(iommu_heap);
	return ERR_PTR(-ENOMEM);
	}

	void ion_iommu_heap_destroy(struct ion_heap *heap)
	{
	struct ion_iommu_heap *iommu_heap =
	container_of(heap, struct ion_iommu_heap, heap);

	kfree(iommu_heap);
	iommu_heap = NULL;
	}